HDMI monitor not recognised anymore

Hello,

After connecting my external HDMI monitor (LG Flatron E2251VR-BNW) to an Android TV box (Mi Box 3), my MacBook Pro Retina Early 2013 2.7 i7 is not recognising it anymore.

What I did was connect the monitor to the Mi Box 3, put the Mi Box to sleep and then connect it to the MBP again.

I already deleted the com.apple.windowserver..... preference files, but it's still not recognised.

Other HDMI monitors are working and the monitor itself is working with other hardware, so it's the MBP-LG connection which was messed up somehow.

I am on macOS 10.14.1.

Can anyone help me fix this?

Thank you!